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National Center for Health Statistics
Edward J. Sondik, Ph.D.,Director
Jack R. Anderson,Deputy Director
Jack R. Anderson,Acting Associate Director forInternational Statistics
Lester R. Curtin, Ph.D.,Acting Associate Director forResearch and Methodology
Jacob J. Feldman, Ph.D.,Associate Director for Analysis,Epidemiology, and Health Promotion
Gail F. Fisher, Ph.D.,Associate Director for Data Standards,Program Development, and Extramural Programs
Edward L. Hunter,Associate Director for Planning, Budget,and Legislation
Jennifer H. Madans, Ph.D.,Acting Associate Director forVital and Health Statistics Systems
Stephen E. Nieberding,Associate Director forManagement
Charles J. Rothwell,Associate Director for DataProcessing and Services
W. Edward Bacon, Ph.D.,Director, Division of Health CareStatistics
Phillip R. Beattie,Director, Division of Data Services
Mary Anne Freedman,Director, Division of Vital Statistics
Ann M. Hardy, Dr.P.H.,Acting Director, Division of HealthInterview Statistics
Delton Atkinson,Director, Division of Data Processing
Jennifer H. Madans, Ph.D.,Director, Division ofEpidemiology
Diane M. Makuc, Dr.P.H.,Director, Division of Health andUtilization Analysis
Clifford L. Johnson,Acting Director, Division of HealthExamination Statistics
Diane K. Wagener, Ph.D.,Acting Director, Division ofHealth Promotion and Statistics
Contents
National Center for Health Statistics organization chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
Overview and Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Surveys and Data Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1National Vital Statistics System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
National Maternal and Infant Health Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1National Mortality Followback Survey. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Linked Files of Live Birth and Infant Death Records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2National Death Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
National Survey of Family Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2National Health Interview Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2National Health and Nutrition Examination Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
National Hispanic Health and Nutrition Examination Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4National Health and Nutrition Examination Survey (NHANES) IEpidemiologic Follow-up Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
National Health Care Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4National Hospital Discharge Survey. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4National Ambulatory Medical Care Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4National Survey of Ambulatory Surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4National Hospital Ambulatory Medical Care Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5National Home and Hospice Care Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5National Nursing Home Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5National Health Provider Inventory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
National Employer Health Insurance Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5National Immunization Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5State and Local Area Integrated Telephone Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Research and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Cognition and Survey Measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Statistical Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Statistical Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Survey Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Automation Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Analytical Products and Dissemination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Electronic Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Major Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Interaction with Users and Collaborators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8National Committee on Vital and Health Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DHHS Data Council . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Nutrition Monitoring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8NCHS Data Users Conference and Public Health Conference on Records and Statistics . . . . . . . . . . 9Reimbursable Work Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Technical Assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Minority Statistics and Grants. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9International Collaboration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Appendix
I. Summary of Surveys and Data Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
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Overview and BackgroundThe National Center for Health Statistics (NCHS) is a unique public resource for health information. As the
Nation’s principal health statistics agency, NCHS provides statistical information to guide actions and policies toimprove the health of the American people. NCHS’s mission is to monitor America’s health, and our activitiesmirror the multi-faceted aspects of health care.
NCHS surveys and data systems provide fundamental public health and health policy statistics that meet theneeds of a wide range of users. NCHS data are used to track changes in health and health care, particularly asmajor changes are occurring in private markets and in Federal and State policy. NCHS provides mechanisms forobtaining consistent, uniform statistics that allow for comparison across population groups, types of health careproviders, and States; for planning, targeting, and assessing the effectiveness of public health programs, and foridentifying health problems, risk factors, and disease patterns. This type of information is important tounderstanding trends that allow NCHS to anticipate the future directions in the health care system and in healthbehaviors.
In 1960 the National Office of Vital Statistics and the National Health Survey merged to form NCHS. Since1987 NCHS has been a part of the Centers for Disease Control and Prevention. Under Sections 304, 306, and 308of the Public Health Service Act, NCHS has legislative authority for its programs. The Act authorizes datacollection, analysis, and dissemination of a broad range of health and health-related areas and provides specificlegislative authority to enable the Center to protect the confidentiality of information received in its surveys. Inaddition the Act provides for NCHS to undertake and support research, demonstrations, and evaluationsregarding survey methods and to provide technical assistance to State and local jurisdictions.
Surveys and Data Systems
Information plays a critical role in public healthand health policy. NCHS obtains statistics through abroad-based program of ongoing and special studies,including household interview surveys, examinationsurveys, surveys of health care providers, and collec-tion of statistics on birth and death in partnershipwith State government. For additional information onNCHS data systems and programs, refer to the appen-dix in the back of this publication.
National Vital Statistics System
The National Vital Statistics System is responsiblefor the Nation’s official vital statistics. These vitalstatistics are provided through State-operated registra-tion systems and are based on vital records filed inState vital statistics offices. The registration of vitalevents—births, deaths, marriages, divorces, fetaldeaths, and induced terminations of pregnancy—is aState function. NCHS cooperates with the States todevelop and recommend standard forms for data col-lection and model procedures to ensure uniform regis-tration of the events. The Center shares the costsincurred by the States in providing vital statistics datafor national use.
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Detailed annual data on births, deaths (includinginfant deaths), fetal deaths, and terminations of preg-nancy are available for the United States and forStates, counties, and other local areas. Monthly provi-sional data are available for the United States andeach State. For marriage and divorce, monthly totalsare available.
National Maternal and Infant Health Survey—The objective of the survey is to collect data needed byFederal, State, and private researchers to study fac-tors related to poor pregnancy outcomes, including lowbirthweight, stillbirth, infant illness, and infant death.It provides data on socioeconomic and demographiccharacteristics of mothers, prenatal care, pregnancyhistory, occupational background, health status ofmother and infant, and types and sources of medicalcare received. Information is based on data collectedfrom questionnaires administered to mothers, physi-cians, hospitals, and other medical providers associ-ated with outcomes.
The 1988 survey expanded on information avail-able for birth, fetal death, and infant death vitalrecords, and was the first national survey that includeddata on those three pregnancy outcomes simulta-
neously. A 1991 longitudinal followup of respondentsin the NMIHS was conducted to obtain national esti-mates and health status information on a nationallyrepresentative sample of 3-year old children.
Earlier studies included National Natality Sur-veys in 1963, 1964–66, 1968–69, 1972, and 1980. ANational Fetal Mortality Survey was conducted in1980, and a National Infant Mortality Survey wasconducted in 1964–66.
National Mortality Followback Survey—Information from this survey expands information onthe death certificate to help researchers identify howlifestyles affect health and the extent of the burden ofillness in the last year of life. The data provide infor-mation on socioeconomic characteristics of deceasedpersons, use of and payment for hospitals and institu-tional care during the last year of life, and factorsrelated to health status, such as smoking habits.
The survey was conducted annually from 1961 to1968 and then in 1986. The 1986 survey sample wasapproximately 1 percent of U.S. resident deaths ofpersons 25 years of age and over. If death occurred in ahospital or institution, a questionnaire was also sentto the facility.
The most recent survey was initiated in 1993 andit is the first survey to collect information from medi-cal examiners and coroners for external causes ofdeath.
Linked Files of Live Birth and Infant DeathRecords—The purpose of this data set is to provideinformation needed for detailed analyses of infantmortality trends and differentials in the United States.In the linked birth/infant death data set the deathcertificate is linked to the corresponding birth certifi-cate for each infant under 1 year of age who dies in theUnited States. The purpose of the linkage is to use themany additional variables available from the birthcertificate in infant mortality analyses. The linkedbirth/infant death data set is the only source of nationalrecord-based data on infant mortality by birthweight,gestational age, prenatal care utilization, cause ofdeath, and on maternal characteristics such as age,education, marital status, and smoking and alcoholuse during pregnancy. Infant mortality rates for detailedrace and Hispanic-origin subgroups are available fromthis data set, which permits use of the more accuraterace and Hispanic origin data from the birth certifi-cate. Unit record linked file data are available onpublic-use data tapes for 1983–91 birth cohorts and onCD-ROM for the 1985–91 birth cohorts.
National Death Index—Working with State offices,NCHS established the National Death Index (NDI) asa resource to aid epidemiologists and other health andmedical investigators with their mortality ascertain-ment activities. The NDI is a central computerizedindex of death record information compiled from mag-netic tapes submitted by State vital statistics offices.
Beginning with 1979 deaths, death records are addedto the NDI file annually, approximately 10 monthsafter the end of a particular calendar year.
The index assists investigators in determiningwhether persons in their studies have died and, if so,provides the names of the States in which those deathsoccurred, the dates of death, and the correspondingdeath certificate numbers. Investigators also will soonbe able to receive the coded causes of death or (as inthe past) can arrange with the appropriate Stateoffices to obtain copies of death certificates.
The index is available to investigators solely forstatistical purposes in medical and health research. Itis not accessible to organizations or the general publicfor legal, administrative, or genealogy purposes. Touse the system, investigators must first submit anNDI application form to NCHS. Applicants shouldallow about 2 months for their applications to bereviewed and approved. Once approved for NDI filesearches, users may submit records of their studysubjects to NCHS on magnetic tape or floppy disk.Users should submit as many of the following dataitems as possible for each study subject first and lastname, middle initial, father’s surname, social securitynumber, date of birth, sex, race, marital status, Stateof last known residence, State of birth, and age atdeath (if known).
National Survey of Family Growth
The National Survey of Family Growth (NSFG) isa multipurpose survey based on personal interviewswith a national sample of women 15–44 years of age inthe civilian noninstitutionalized population of theUnited States. Its main function is to collect data onfactors affecting pregnancy and women’s health in theUnited States. Previous NSFG surveys were con-ducted in 1973, 1976, 1982, 1988, and 1990. The latestsurvey was conducted in 1995.
National Health Interview Survey
The National Health Interview Survey (NHIS) is aprincipal source of information on the health of thecivilian noninstitutionalized population. The survey,conducted annually since 1957, collects informationfrom approximately 40,000 households and 100,000people on health status, access to care and insurance,health services utilization, health behaviors, and othertopics. The survey consists of a set of basic data itemsthat are repeated each year and additional questionsthat can change each year to address current healthtopics.
Basic annual data are collected on the incidence ofacute conditions, episodes of persons injured, prevalenceof chronic conditions and impairments, restriction in
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activity due to impairment or health problems,respondent-assessed health status, utilization of healthcare services involving physician care, health insurance,and demographic and socioeconomic characteristics.
Supplemental questions addressing major healthissues have included a variety of topics. Questionson AIDS knowledge and attitudes have been includedannually as a special health topic since 1987. Otherspecial topics have included immunization, familyresources and health insurance, cancer control, can-cer epidemiology, disability, youth risk behaviors,and data items to measure national progress towardachieving the objectives set in Healthy People 2000:National Health Promotion and Disease PreventionObjectives.
NHIS is a major part of the Department of Healthand Human Services’ (DHHS) integration plan, aneffort to improve the quality, efficiency, and timelinessof data by integrating surveys. The NHIS nationalsample is used as the sampling frame for other DHHSsurveys including the National Medical ExpendituresPanel Survey, and is linked to the sample of theNational Health and Nutrition Examination Surveyand the National Survey of Family Growth.
As part of the integration plan, NHIS has beenredesigned to give more emphasis to personal healthcharacteristics such as disability and less emphasis tomedical events such as hospitalization. It will obtaininformation on fewer types of chronic conditions thanin the past, but will produce more reliable estimatesfor the conditions it does cover. More complete infor-mation on injuries and on children will also be avail-able. The data collected will be more useful for diseaseand risk factor surveillance and will be better able toaddress emerging health issues.
Concurrent with the survey redesign, NHIS haschanged from traditional paper and pencil for datacollection to computer-assisted personal interviewing.This will significantly reduce the time between collect-ing and disseminating the data.
Targeted population studies—In targeted popula-tion studies, persons or families are selected fromNHIS participants, and additional health-related infor-mation is obtained by reinterviewing them or by obtain-ing information from linking NHIS data files withother health data files. This approach facilitates thecollection of detailed information from the target popu-lation over time and may be used for studies requiringmore detail about prevalence of selected conditions ordiseases.
Targeted population studies undertaken by NCHSand collaborating agencies have included the following:
+ The Longitudinal Study of Aging (LSOA)-1, basedon the 1984 NHIS Supplement on Aging, and theLSOA-2, based on the 1994 NHIS, both conductedjointly with the National Institute on Aging.
+ The Teenage Attitudes and Practices Survey, con-ducted jointly with the Office on Smoking andHealth with data collected during the 1989–90school year.
+ The Access to Care Followup study, a 1994 tele-phone survey including segments of the generalpopulation and those persons with asthma orischemic heart disease. This study was conductedjointly with the Robert Wood Johnson Foundation.
+ The Disability Followup Survey, a 1994–95 surveyincluding adults, children, and polio survivors, con-ducted jointly with a number of other organiza-tions including the DHHS Office of the AssistantSecretary for Planning and Evaluation, the SocialSecurity Administration, the Institute for Disabil-ity and Rehabilitation Services, and the RobertWood Johnson Foundation.
National Health and NutritionExamination Survey
Since 1960 NCHS has collected information on thehealth of Americans through a combination of inter-views and direct physical examinations. For theNational Health and Nutrition Examination Survey(NHANES), standardized medical examinations areconducted and physical measurements are taken on anationally representative population.
The goals of the survey are as follows:
+ To estimate the number and percent of persons inthe U.S. population and designated subgroups withselected diseases and risk factors
+ To monitor trends in the prevalence, treatment,and control of selected diseases
+ To investigate risk factors for selected diseases+ To monitor trends in risk behaviors and environ-
mental exposures+ To study the relationship between diet, nutrition,
and health+ To explore emerging public health issues
NHANES III is the most recent of seven healthexamination surveys and was completed in 1994. Itprovides information on 30 topics including blood pres-sure, blood cholesterol, obesity, passive smoking, lungdisease, osteoporosis, HIV, hepatitis, immunization sta-tus, diabetes, allergies, growth and development, bloodlead, anemia as well as information on nutritionalstatus, dietary intake and nutritional blood measures.
The eligible population for this survey was theU.S. civilian noninstitutionalized population aged 2months and over. Forty-thousand persons of all raceswere selected from 81 counties, which were selectedfrom 26 States. About 30,000 people agreed to partici-pate in the medical examination. Children, older per-sons, African Americans, and Mexican Americans were
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oversampled to provide precise estimates for theserelatively small subsets of the populations.
Planning is currently underway for NHANES IVto be conducted beginning in 1998 and continuingthrough 2004. Numerous organizations are participat-ing in the planning including virtually all Federalhealth agencies, the academic community, and theprivate sector.
National Hispanic Health and Nutrition Examina-tion Survey—This one-time health examination surveyfocused on three major subgroups of the Hispanicpopulation—Mexican Americans in the Southwest,Cubans in Miami (Dade County), Florida, and PuertoRicans in the New York City area. This survey wasconducted from 1982 to 1984 and provides health andnutrition data on a 12,000-person sample.
NHANES I Epidemiologic Follow-Up Study—Using information gathered in NHANES I, conducted1971–75, researchers are investigating the relation-ship between selected clinical, nutritional and behav-ioral factors and subsequent morbidity, mortality, andinstitutionalization. The NHANES I EpidemiologicFollow-Up Study is a collaborative project involvingNCHS and other organizations in the Centers forDisease Control and Prevention, the National Insti-tute on Aging and other components of the NationalInstitutes of Health, and the Substance Abuse andMental Health Administration.
The NHANES I Epidemiologic Follow-Up Studyincludes the 14,407 participants who were 25–74 yearsof age when first examined. The first wave of datacollection was conducted in 1982–84. It included trac-ing all participants and conducting face-to-face inter-views with found participants or their proxies. For allparticipants, hospital and nursing home records ofovernight stays were collected. For those who werealive, pulse rate, weight, and blood pressure weretaken. For those participants who were deceased, deathcertificates were obtained.
Subsequent followups used similar design and datacollection procedures, with the following exceptions: A30-minute computer-assisted telephone interview wasused instead of face-to-face interview; no physical mea-surements were taken; in 1986 the study includedthose who were aged 55–74 years during the NHANESI and who were not known to be deceased; and in 1987and 1992, the study was conducted on all livingparticipants.
National Health Care Survey
To meet the health statistics needs of the future, anumber of the Center’s record-based surveys weremerged and expanded into one survey of health careproviders called the National Health Care Survey(NHCS). The NHCS provides data on health care
settings such as hospitals, ambulatory surgical cen-ters, hospital outpatient departments, emergencydepartments, nursing homes, hospices, and home healthagencies. Thus the survey is a source of a wide rangeof data on the health care field and a significantresource for monitoring health care use, the impact ofmedical technology, and the quality of care provided toa changing American population.
NHCS was built upon three NCHS surveys: theNational Hospital Discharge Survey, the NationalAmbulatory Medical Care Survey, and the NationalNursing Home Survey. These were complemented bythree new surveys; the National Survey of AmbulatorySurgery, the National Hospital Ambulatory MedicalCare Survey, and the National Home and HospiceCare Survey.
National Hospital Discharge Survey—The NationalHospital Discharge Survey is the principal source ofinformation on inpatient utilization of hospitals. Con-ducted annually since 1965, the survey provides dataon the use of non-Federal short-stay hospitals, on theirsize, location and ownership as well as data on diag-noses, surgical procedures, length of stay, expectedsource of payment and patient characteristics. Datafrom the NHDS are useful for tracking specific dis-eases, the introduction of new technologies, and theimpact of changes in the financing systems. The sur-vey is based on data abstracted from 274,000 recordsfrom 500 hospitals.
National Ambulatory Medical Care Survey—TheNational Ambulatory Medical Care Survey providesdata on visits to physicians, including information onpatient characteristics, diagnostic procedures, patientmanagement, and planned future treatment. The sur-vey was conducted annually from 1974–81, in 1985,and annually since 1989.
Data are collected using encounter forms fromapproximately 3,000 physicians from a sample of 40,000visits. Data collection from the physician, rather thanfrom the patient, provides an analytic base that expandsinformation on ambulatory care collected through otherNCHS surveys.
National Survey of Ambulatory Surgery—Although data have been available for three decadesfor surgery on inpatients, advances in medical technol-ogy permit a wide variety of surgical and diagnostictreatments outside the inpatient setting. The NationalSurvey of Ambulatory Surgery provides detailed dataon the use of free-standing and hospital-based ambu-latory surgery in the United States.
Data collection began in 1994 and data are avail-able on patient characteristics including age and sex;administrative information including patient disposi-tion, expected sources of payment, and region of thecountry where surgery was performed; and medicalinformation including diagnoses, surgical operations,and diagnostic procedures performed.
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National Hospital Ambulatory Medical CareSurvey—The National Hospital Ambulatory MedicalCare Survey provides data representing the experi-ence of the U.S. population in hospital emergencydepartments and outpatient departments. Specifically,the survey provides information on the demographiccharacteristics of patients, expected source of pay-ment, patients’ complaints, physicians’ diagnoses, diag-nostic and/or screening services, procedures, medicationtherapy, disposition, types of health care professionalsseen, and causes of injury where applicable.
Data collection began in 1992 and has continuedannually. Data are abstracted from 70,000 medicalrecords of visits to 440 hospitals.
National Home and Hospice Care Survey—TheNational Home and Hospice Care Survey providesdata on home health agencies and hospices and theircurrent patients and discharges. Conducted annuallyfrom 1992–94 and in 1996, the survey was establishedin response to the rapid growth in the number of homehealth agencies and hospices throughout the UnitedStates and the need to assess the availability andutilization of these services.
Personal interviews with administrators and staffprovide information from approximately 1,500 sampleagencies. Data are collected on referral and length ofservice, diagnoses, number of visits, patient charges,health status, reason for discharge, and types of ser-vices provided.
National Nursing Home Survey—The NationalNursing Home Survey provides information on nurs-ing homes from two perspectives—that of the providerof services and that of the recipient. Data about thefacilities include characteristics such as size, owner-ship, Medicare and/or Medicaid certification, occu-pancy rate, services provided, and expenses. Forrecipients, data are obtained on demographic charac-teristics, health status, and services received.
Conducted periodically since 1963 and most recentlyin 1995, the survey is based on data collected ininterviews with administrators and staff in a sampleof about 1,500 facilities.
National Health Provider Inventory—The NationalHealth Provider Inventory provides the sampling framefor the National Nursing Home Survey and the NationalHome and Hospice Care Survey. This inventory is acomprehensive national listing of nursing homes, resi-dential care facilities, hospices, and home health agen-cies. It is an important source of national statistics onthe number, type, and geographical distribution ofhealth providers in the United States. It has beenupdated periodically since 1963 under different titles—the National Master Facility Inventory (1967–82) andthe Inventory of Long-Term Care Places (1986). Mostrecently it was updated in 1991.
Based on data collected on self-administered ques-tionnaires sent directly to agencies and facilities, the
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inventory provides names and addresses of almost56,000 facilities, including more than 15,500 nursinghomes, over 31,000 board and care homes and morethan 7,800 home health agencies and hospices. Infor-mation such as type of facility, ownership, size, loca-tion, and resident characteristics is available as wellas information on number of clients, services, andlocations.
National Employer HealthInsurance Survey
The National Employer Health Insurance Surveyis a national survey of establishments in the privateand public sectors conducted to examine characteris-tics of employer-sponsored health insurance. The datacollected provide information on private health insur-ance coverage. The study was sponsored by the Depart-ment of Health and Human Services and managed bythe National Center for Health Statistics.
Data were collected from 39,000 businesses andorganizations, primarily using computer-assisted inter-views, between April and December 1994.
National Immunization Survey
The National Immunization Survey was estab-lished in 1994 to provide high quality, timely data onimmunization coverage of children 19–35 months ofage. The data are used to monitor immunization cov-erage in the preschool population in 50 States and 28large urban areas. The survey is a collaborative effortbetween NCHS and the Centers for Disease Controland Prevention’s National Immunization Program.
State and Local Area IntegratedTelephone Survey
In response to the need for the development of anational capacity to generate high quality State leveldata for tracking and monitoring current and emerg-ing health and welfare policy-related issues, the Stateand Local Area Integrated Telephone Survey (SLAITS)was initiated. SLAITS was designed to provide quickturnaround data on a variety of broad health andwelfare related issues and includes questions on healthinsurance coverage, access to care, health status, uti-lization of services and basic demographic and socio-economic information taken from the National HealthInterview Survey. It uses the same telephone designapproach as used in the National Immunization Sur-vey. The study will provide a mechanism for State andnational comparisons of data and also allow for cus-tomization for State specific needs. Data collection fora number of pilot States were conducted in 1997.
d Methods
Research anNCHS maintains an active program in statisticalresearch and methodology. The major components ofthat program are briefly described below.
Cognition and Survey Measurement
The National Laboratory for Collaborative Researchin Cognition and Survey Measurement applies cogni-tive methods in questionnaire design research, andwas a pioneering effort when established in 1985. Incollaboration with other Center programs, the Labora-tory develops and tests NCHS data collection instru-ments. It also supports a questionnaire design researchprogram in collaboration with university scientists bymeans of research contracts.
Statistical Methods
Research is undertaken at the Center on analyticmethods applicable to the NCHS registration systemsand sample surveys. Current projects include the devel-opment of computer software for the analysis of surveydata, methods for model and design-based State esti-mates, and random effect models for analyzing longi-tudinal data.
Statistical Technology
The Center conducts a program of contract andintramural research on automated statistical andgraphical technology. Current applications include auto-mated mapping, statistical computing methods, geo-graphic information systems, statistical graphics, andstatistical atlases.
Survey Design
The Survey Design program involves the designand evaluation of the sample plans for many of NCHS
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s surveys to improve their efficiency and analyticalcapability. Current research focuses on linked surveydesigns, designs for State telephone surveys, nonre-sponse adjustments, and estimation of sampling errorsfor rare events. In addition, the Center maintains anactive program in monitoring data quality.
Automation Activities
A continuing initiative of NCHS is automation ofdata collection, analysis, and dissemination. Computer-assisted personal and telephone interviews are beingconducted to improve the quality and timeliness ofdata collection. Automation of data collection has alsobeen successfully achieved with NCHS s medical exami-nation centers, where data are collected for the NationalHealth and Nutrition Examination Surveys. The devel-opment and field testing of automated medical codingsystems is another automation effort in data collec-tion. These systems provide the potential for moretimely processing of vital statistics at the local, State,and Federal levels and are essential to the goal ofautomating the collection of vital statistics at thesource.
In recent years NCHS has expanded electronicaccess to information. National public-use data filesincluding all documentation are now available onCD-ROM. These data are presented using the Center’sStatistical Export and Tabulation System (SETS). TheSETS software is also available as a toolkit for devel-opers to prepare large read-only databases for distri-bution on CD-ROM. A Windows 95TM version of SETSis now available. The new software, which incorpo-rates all the advantages of multitasking found inWindow 95TM, supports all the powerful aspects of theearlier DOS version and adds a unique charting capa-bility to the spreadsheet functions.
Analytical Products and Dissemination
A central component of the mission of NCHS is todisseminate its vital and health statistics and researchfindings to as wide an audience as possible. NCHSdata are presented in a variety of electronic productsand publications, including journal articles andchartbooks.
To assist data users, NCHS operates a full-service,centralized information program that provides refer-ence, inquiry, and referral service to help users locateand use NCHS data and to identify other data sources.
Electronic Products
NCHS has an extensive program of data releasethrough electronic media including the World WideWeb, CD-ROMS with statistical software, CD-ROMswith text-retrieval software, and public-use data tapes.
Home Page
The NCHS home page provides instantaneousaccess to a wide range of statistical information abouthealth status and use of health care in the UnitedStates. The NCHS Web site includes links to the latestsocial statistics from Federal agencies; a link to FED-STATS with over 70 links to other Federal statisticalagencies; a data warehouse with detailed statisticaltables, links to CDC’s WONDER data retrieval sys-tem, and other data sites; news releases and factsheets, frequently asked questions, and sections onwhat’s new, coming events, and NCHS products. Full-text files of catalogs and publications may be viewed,searched, printed, and downloaded. The Web page alsofeatures a query section where users have an opportu-nity to direct statistical questions to NCHS technicalinformation specialists and to provide comments onthe home page and other Center activities.
CD-ROMs
Statistical CD-ROMs containing micro-data are nowavailable from many of the Center’s data collection pro-grams. These CD-ROMs contain detailed data files; theassociated documentation; and Statistical Export andTabulation System (SETS) software to retrieve, access,and search data and documentation. Text CD-ROMscontaining NCHS publications are also available. Thesepublications can be viewed, searched, printed, and down-
loaded using the Adobe Acrobat software on theCD-ROMs. Refer to the most recent Catalog of ElectronicProducts for additional information.
Data Tapes
Over 600 public-use data tapes have been pro-duced by the Center. Data tapes available throughNCHS parallel the various data systems and representthe full range of data collected by NCHS. The majorityof NCHS data tapes are microdata rather than sum-mary analyses; individual identifiers have beenremoved. NCHS data files are sold through the NationalTechnical Information Service. Purchase price for thefile includes complete documentation. Data tapes aredescribed in the Catalog of Electronic Products and inperiodic updates.
Major Publications
NCHS publications are indexed in catalogs of pub-lications of the National Center for Health Statistics.Major publications are as follows:
n Health, United StatesA comprehensive annual report from the Secretaryof Health and Human Services to the President andthe Congress on the health of the Nation. Health,United States presents current and trend data onhealth status and determinants, utilization of healthresources, health care resources, and health careexpenditures.
n Vital and Health Statistics SeriesBackground, methodology, and analytical studiesand presentations of findings from NCHS data col-lection programs.
n Advance Data From Vital and Health StatisticsSummary reports that provide the first release ofdata from NCHS health and demographic surveys.
n Vital Statistics of the United StatesHistorical marriage and divorce data through 1988and on-going annual compilations of mortality andnatality data, with extensive demographic and geo-graphic detail.
n Monthly Vital Statistics ReportMonthly and cumulative data on vital events, withbrief analyses.
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Interaction with Users and Collaborators
A primary mission of NCHS is to meet the healthdata needs of other agencies of the Department ofHealth and Human Services and other data users. TheCenter accomplishes this through several programsthat promote interaction with users and collaborators.
National Committee on Vital andHealth Statistics
The National Center for Health Statistics providesstaff support for the National Committee on Vital andHealth Statistics (NCVHS) and its subcommittees.The NCVHS is the official external advisory committeeon health statistics to the Secretary of Health andHuman Services.
The Committee consists of 16 individuals distin-guished in the fields of health statistics, epidemiology,and health care services. The Committee fulfills impor-tant review and advisory functions relative to healthstatistical problems of national or international inter-est, stimulates or conducts studies of such problems,and makes proposals for improvement of the Nation’shealth statistics and information systems.
The NCVHS serves as a national forum for thecollaboration of interested parties with the long-termgoal of improving the comparability of private sector,State, and Federal health information systems whileassuring the confidentiality of the information col-lected. The committee’s new charter enables theNCVHS to foster collaboration on a voluntary meansto facilitate and accelerate the development of consen-sus across the public and private sectors around thesekey data standards.
NCVHS has become increasingly active over thepast several years, addressing issues relating to uni-form health data sets, medical classification systems,the need for improved mental health statistics, dataneeds for minority health and the medically indigent,and State and community health data needs.
DHHS Data Council
The Director of NCHS serves as the Senior Advisoron Health Statistics to the Secretary of Health andHuman Services (HHS) In this role he serves as amember of the DHHS Data Council. Other membersinclude the HHS Privacy Advocate and Assistant Sec-retary and Agency Administrator-level HHS officialswho have a direct reporting relationship to the Secre-tary of Health and Human Services.
Established in 1995, the Data Council meetsmonthly to coordinate all health and nonhealth datacollection and analysis activities of the Department ofHealth and Human Services through an integrated
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health data collection strategy, coordination of healthdata standards, and health information and privacyactivities.
The majority of the Data Council’s work is per-formed by issue-specific, inter-agency standing and adhoc staff committees and working groups. Agendaitems include: develop a Department-wide data collec-tion strategy, including coordination and integration ofsurveys and oversight of surveys and general statisti-cal analysis; coordinate HHS and Inter-Departmenthealth data standards activities; serve as HHS liaisonfor the NCVHS; serve as focus for HHS issues relatingto privacy of health and social services information;provide a forum for coordination of health and humanservices issues raised by the expanding National Infor-mation Infrastructure activities; and provide a forumfor coordination of HHS responses to external requestsfor HHS action on issues related to health and socialservices data.
Nutrition Monitoring
NCHS plays a major role in monitoring the nutri-tional and health status of the American population.Working with members of the Interagency Board forNutrition Monitoring and Related Research (IBN-MRR), NCHS provides information about dietary andnutritional status, conditions that affect dietary andnutritional status, and the relationship between dietand health.
The IBNMRR oversees implementation of the10-Year Comprehensive Plan for the National Nutri-tion Monitoring and Related Research Program. ThePlan was formally sent to Congress in January 1993.The goals of the plan are to:
+ collect quality data that are continuous, coordi-nated, timely, and reliable
+ use comparable methods for collecting data andreporting the results
+ conduct related research and+ efficiently and effectively disseminate and exchange
information with data users
This information is used to set nutrition policy,evaluate programs, and develop and plan nutritionand health education and intervention programs.
The IBNMRR coordinates the preparation of direc-tories and Federal and State nutrition monitoringactivities, reports of findings from the National Nutri-tion Monitoring and Related Research Program, andperiodic scientific reports to Congress, Federal andState organizations, researchers, and the media. Themost recent report, Third Report on Nutrition Monitor-ing in the United States, was published in 1995.
NCHS Data Users Conference andPublic Health Conference on
Records and Statistics
NCHS holds a Data Users Conference for currentand potential users of NCHS data. The Conferenceprovides an opportunity to meet with and ask ques-tions of NCHS staff and to learn about present andfuture plans for NCHS data collection, analysis, anddissemination activities. The Conference program con-sists of plenary sessions featuring key NCHS staff,workshops on all of the NCHS data files, and sessionson cross-cutting topical and analytical issues of publichealth concern. The Public Health Conference onRecords and Statistics (PHCRS) has been sponsoredby the National Center for Health Statistics as aperiodic meeting since 1958. PHCRS provides a forumfor representatives from Federal, State, and local gov-ernments, as well as from universities and profes-sional associations, to share their knowledge andexperience. This diverse gathering lends the Confer-ence a rich variety of perspectives on current issuesconcerning health information in the United States.Technical and philosophical issues are brought to lightduring each Conference session. The proceedings arepublished and serve as a valuable reference tool inaddressing issues raised at the Conference. In 1997,the two meetings were combined into one Conference.
Reimbursable Work Program
Many NCHS data systems are designed to allowflexibility in content in targeting special populations.This flexibility allows NCHS to add questions or exami-nation procedures to existing data collection mecha-nisms and to target population subgroups (for example,older persons, Hispanics, and blacks) in its surveys.
Agencies with data requirements frequently areable to work with NCHS to meet their needs throughmodifications or additions to NCHS data systems,eliminating the need to mount new data collectionefforts that may be costly or may duplicate existingefforts. NCHS is reimbursed by these agencies forcosts incurred in providing such services.
Technical Assistance
NCHS offers technical assistance to interested par-ties in the areas of health statistics development andin access to or use of existing health-related data. Staffmembers from the major survey divisions of NCHS arefrequently called upon to assist in developing samplesurvey questionnaires, methods, and procedures. Otherresearch or analytical staff provide assistance in theareas of survey design, estimation, and analyticalmethods. Where design-based estimates for small areas
are impossible from existing survey vehicles, NCHSprovides guidance in the development of and use ofmodel-based estimates.
NCHS uses a variety of opportunities to shareplans, developments, and analyses. These include uni-versity lectures and seminars; data system seminars;special topic seminars; presentation of research find-ings at annual association meetings; conferences, work-shops, symposiums, and ad hoc site visits for uniqueproblem solutions.
Minority Statistics and Grants
For several decades, NCHS has held a leadershiprole in highlighting the health of racial and ethnicpopulations in the United States, and in calling atten-tion to the significant differences that exist betweenvarious population groups.
NCHS data programs provide the statistics toprofile the health of minority populations in the UnitedStates. Vital statistics provide information on lifeexpectancy, infant mortality, and patterns of birth byprenatal care and birthweight. Other data to deter-mine the prevalence of major chronic conditions—suchas heart disease, hypertension, and diabetes—and theuse of hospital and physician services are providedthrough health surveys. In general, all NCHS datasystems make special efforts to make estimates for theblack and Hispanic populations, but are limited intheir ability to provide data for Asian or Pacific Island-ers, and for American Indians or Alaskan Natives.NCHS is continuing its efforts to improve the availabil-ity of data for minority populations. These effortsinclude oversampling of minority populations in NCHSsurveys to improve the precision of the estimates madebased on the collected data, modification of codingmethodologies to provide data for subpopulations ofthe broader racial and ethnic groups, and increasedpublication of data for racial and ethnic minoritypopulations. NCHS has conducted the Hispanic Healthand Nutrition Examination Survey that includes arange of data on chronic conditions, disability, growth,and physical development.
As a result of legislation passed in 1990, an extramu-ral grants program to improve minority statistics wasestablished by NCHS. Grants were authorized for thesupport of studies to fill in gaps where national surveyscannot provide sufficient data; analysis of existing data;and research to improve methods for obtaining informa-tion on racial and ethnic subpopulations.
International Collaboration
The National Center for Health Statistics (NCHS)maintains international health statistics programs withdeveloped and developing countries all around the
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world. These programs consist of cooperative venturesand collaborative research on analytical and method-ological issues, technical assistance and consultation,training and information exchange, and joint activitieswith multinational agencies. In addition, NCHS spon-sors international meetings and symposiums, and con-tributes to other international forums through scientificarticles and presentations. Through these efforts, NCHSseeks to improve the availability and quality of healthdata in the United States and other countries.
The international research program is carried outin collaboration with other countries and with otheragencies of the HHS. An important part of this researchis carried out through International CollaborativeEfforts (ICE’s), which bring together domestic andforeign experts to focus on specific health issues ofmutual interest to the participating countries. Researchfindings from these analytic research projects are usedto provide guidance to specific HHS programs and toimprove the health statistical activities of NCHS. Cur-rent topics included in these collaborative researchprojects are perinatal and infant mortality, health andhealth care of the elderly, and injuries. Under develop-ment is a new ICE on the automated classification ofcauses of death.
The Center directly supports the World HealthOrganization (WHO) in worldwide health statisticsactivities by promoting domestic and internationaldevelopment and use of the International Classifica-tion of Diseases and the International Classification ofImpairments, Disabilities, and Handicaps. This isaccomplished through the WHO Collaborating Centerfor Classification of Diseases for NorthAmerica, housedat NCHS. NCHS also serves as the WHO Collaborat-ing Center for Health and Nutrition ExaminationSurveys, helping to disseminate its unique capabilitiesin complex health survey design and health examina-tion data collection and analysis.
For additional information about the National Centerfor Health Statistics, contact:
Data Dissemination BranchNational Center for Health Statistics6525 Belcrest Road, Room 1064Hyattsville, MD 20782-2003Telephone (301) 436–8500E-mail: [email protected]: http://www.cdc.gov/nchswww/nchshome.htm
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